This application claims priority of European Patent Application No. 00305790.8, filed Jul. 7, 2000.
The invention relates to a transfer line for the transfer of fluid or powder-like substances from one or more sources to an outlet, such as a filling station, and to a cleaning method and a corresponding cleaning station.
Transfer lines are used in a wide variety of industries. A point of concern is the ability to rapidly clean and change the use transfer lines to allow different products to be transferred to equipment for further processing or, e.g., to filling or packaging machinery.
The issue of cleaning transfer lines and ancillary equipment such as pumps or filters arises for instance with filling machines. Nearly every branch of industry that manufactures liquids, gels or granular products uses filling machines. For example, motor oils, pharmaceuticals, cooking oils, paints, adhesives, sauces, milk, and beer all require to be packed by filling machines into a variety of containers, including glass, metal, and plastics. All of these applications require rapid and complete cleaning of all pumps and pipelines to minimize lost production time.
The time taken to clean the transfer equipment between the packaging of two different products is an unproductive part of the process. In the foodstuffs industry, cleaning must be scrupulous to prevent cross-contamination of products. Insufficient attention to this factor would produce unpleasant taints and in particular, bacterial contamination. In the pharmaceutical industry, cross-contamination of medicines could have serious, even fatal, consequences. Even in the production of decorative paints and similar products, insufficient cleaning will create off-hues and streaks of colour. Incompatibility between synthetic resins may cause gelling or unacceptable rheological effects.
It is well known in the prior art that pipelines can be cleaned by driving a cleaning plug or xe2x80x9cpigxe2x80x9d from a launching station to a receiving station by water, air or the new product travelling through the line. In the last case the pig both cleans the line and separates the products. Pigs may be constructed from foamed or solid elastomeric material and shaped as balls, dumbbells, and mushrooms or as a series of discs. Despite the success of the pigging technique, switching the pipelines of the prior art to a new product without cross-contamination can take a considerable time because of the need to clean transfer pumps, filter units, and the like.
A typical water based paint factory will have several filling lines, packing paint into 1-liter, 2.5-liter, 5-liter, 10-liter, and 20-liter tinplate or plastic containers as required. For special purposes, including promotional offers, other volumes may be used. Hence, in a paint factory, the pipes from the tinting tanks to the filling machines have to be capable of transporting paint in various quantities appropriate to the volumes being packed. Also, various types of paint, described inter alia by such terms as xe2x80x9cMattxe2x80x9d, xe2x80x9cSheenxe2x80x9d, xe2x80x9cSilkxe2x80x9d, xe2x80x9cEggshellxe2x80x9d, and xe2x80x9cGlossxe2x80x9d cannot be intermixed even if the same colour. Ready-mixed colours and tint bases for in-store tinting are required. A range of whites, pale colours, and strong shades is made, together with tint bases. Because of the need to respond rapidly to customer demand and fashion, it is uneconomic to dedicate production lines to a single type of paint, one group of similar colours or even to a narrow range of pack sizes. This calls for transfer lines that are suitable for all products by being rapidly cleanable from end to end, including ancillary plant such as pumps and filters.
The object of the invention is a transfer line suitable for transferring various different products which can be cleaned thoroughly with a minimized loss of production time.
This object is achieved by a transfer line for the transfer of fluid or powder-like substances from one or more sources, e.g. a holding tank, to an outlet, such as a filling station, which has at least one movable section, optionally including associated equipment such as one or more pumps and/or filters. The movable section is releasably engageable with the other sections of the line. This object is also achieved by a method of cleaning a transfer line having at least one first movable section releasably engaged to other sections of the line. The first movable section(s) is released and cleaned while at least one second movable section is coupled to the transfer line to replace the first movable section(s).